The drainage of water, with these measures being carried out, is conventional and is especially essential when heavy diesel machinery is operated under severe use conditions. For example, when using heavy machinery with heavy diesel engines in less highly developed countries, obtaining fuel of Central European quality is difficult. In fact, in countries with difficult climatic conditions and poor infrastructure, users must expect that the available fuel will have significant impurities, in particular a high water content. Construction and agricultural machinery is often fueled from barrels stored and transported more often with little or no covering at all, so that they are exposed unprotected to the elements such as rain.
According to experience, a maximum water content in diesel oil of up to 10% can be expected. Vandalism and corrupt handling can be responsible for these high water contents.
When highly contaminated diesel oil is used, for example, in the tank of a high-performance common rail diesel engine with consumption of approximately 400 l/day, the amount of water to be drained is about 40 l/day. For commercial filters/water separators the capacity in the water collecting tank is at most 0.5 l. In view of this prior art, the operator, to carry out the conventional drainage process, must shut off the engine roughly 80 times during the workday to negate the suction force of the fuel delivery pump counteracting the outflow of water from the filter arrangement. The operator must also open the outflow orifice of the water collecting space to allow the collected water to flow out. If the operator does not observe the requirements, after some time water bleeds through the filter arrangement into the injection system damage it, resulting in very high maintenance costs and a correspondingly long downtime of the pertinent device.